Ehrlichiosis is an infection passed through a tick bite. It can be fatal if left untreated. However, it can be treated with medicine.


Ehrlichiosis is caused by specific bacteria. The bacteria are passed through the bite of a tick. The lonestar tick, deer tick, and dog tick are linked with this infection.

It may take at least 24 hours for the infection to pass through the bite. Not all tick bites will cause an infection. If a tick bites you, watch the area over the next few days. Call your doctor if you develop any symptoms.

Risk Factors

Being in areas known to have ticks increases your risk of infection. This includes outdoor areas with high grass or bushes.

The infection is most often found in the United States in:

  • Mid-Atlantic states
  • Southeastern states
  • South central states

People with weaker immune systems have higher risk of severe infection.


It may take at least 1 to 2 weeks before symptoms develop. The first symptoms are often flu-like symptoms such as:

  • Fever
  • Chills
  • Muscle and joint aches
  • Nausea and loss of appetite
  • Headaches
  • Fatigue

Some may also develop:

  • Stiff neck
  • Confusion

Some people also develop a rash.

An untreated infection can cause problems with breathing and bleeding.

Headache and Neck Stiffness

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You will be asked about your symptoms and health history. You may be asked if you have spent time in areas known for ticks. You may be unaware of a tick bite and there may be no mark. A physical exam will be done.

A blood test may be done to:

  • Confirm the presence of the ehrlichiosis
  • Look for any other infection that may have been passed from the tick
  • Look for any signs of organ damage


Ehrlichiosis can be treated with antibiotics.

Other medicine may be needed to relieve symptoms. They can be stopped once the infection has passed. It may take a few weeks before all the symptoms have passed.


Tick bites can cause a few types of infections. If you are in an area that may have ticks:

  • Learn when ticks are most active in your area. Avoid tall grass, woods, and brush during these times.
  • Wear light colored clothing to make ticks easier to see.
  • Wear long pants and socks. Consider tucking your pants into your socks so the ticks have a harder time getting to your skin.
  • Use a bug repellent that contains DEET. Follow directions for use on the container. DEET should not be used or used with caution on young children.

After being outdoors:

  • Check yourself and your pets thoroughly for ticks.
  • Quickly remove any ticks that you have found.
  • If a tick is attached to the skin, remove it as soon as possible. Grab the tick close to your skin. Pull out with steady upward pressure. Wash the area where the tick was attached with soap and water.


Centers for Disease Control and Prevention
Family Doctor—American Academy of Family Physicians


Public Health Agency of Canada


Ehrlichiosis. American Academy of Family Physicians website. Available at:
...(Click grey area to select URL)
Updated February 2014. Accessed September 23, 2014.
Ehrlichiosis. Centers for Disease Control and Prevention website. Available at:
...(Click grey area to select URL)
Updated July 2017. Accessed September 1, 2017.
Ehrlichiosis and anaplasmosis. EBSCO DynaMed Plus website. Available at: http://www.dynamed... . Updated December 9, 2016. Accessed September 1, 2017.
Last reviewed September 2018 by EBSCO Medical Review Board James Cornell, MD
Last Updated: 9/23/2018

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